Minim : : Wavetable : : warp

warp

Description

Warping works by choosing a point in the waveform, the warpPoint, and then specifying where it should move to, the warpTarget. Both values should be normalized (i.e. in the range [0,1]). What will happen is that the waveform data in front of and behind the warpPoint will be squashed or stretch to fill the space defined by where the warpTarget is. For instance, if you took Waves.SQUARE and called warp( 0.5, 0.2 ), you would wind up with a square wave with a 20 percent duty cycle, the same as using Waves.square( 0.2 ). This is because the crossover point of a square wave is halfway through and warping it such that the crossover is moved to 20% through the waveform is equivalent to changing the duty cycle. Or course, much more interesting things happen when warping a more complex waveform, such as one returned by the Waves.randomNHarms method, especially if it is warped more than once.

Signature

void warp(float warpPoint, float warpTarget)

Parameters

warpPoint — float: the point in the wave for to be moved, expressed as a normalized value.
warpTarget — float: the point in the wave to move the warpPoint to, expressed as a normalized value.

Returns

None

Wavetable

Example

/**
  * This sketch demonstrates many of the methods available for 
  * modifying Wavetables. The controls are as follows:
  * <ul>
  *   <li>n: normalize the waveform</li>
  *   <li>s: smooth the waveform</li>
  *   <li>r: rectify the waveform</li>
  *   <li>z: add noise to the waveform</li>
  *   <li>q/a: scale the waveform up or down</li>
  *   <li>left click and drag: warp the waveform</li>
  *   <li>right click: flip the waveform around the y position of the mouse</li>
  * </ul>
  * The waveform shown in red is the Wavetable being used by the Oscil and 
  * the moving waveform in white is what the output looks like.
  * <p>
  * For more information about Minim and additional features, 
  * visit http://code.compartmental.net/minim/
  */

import ddf.minim.*;
import ddf.minim.ugens.*;

Minim       minim;
AudioOutput out;
Oscil       wave;
Wavetable   table;

void setup()
{
  size(512, 200, P3D);
  
  minim = new Minim(this);
  
  // use the getLineOut method of the Minim object to get an AudioOutput object
  out = minim.getLineOut();
  
  // create a reasonably complex waveform to start, will be slightly different every time
  table = Waves.randomNHarms(16);
  wave  = new Oscil( 440, 0.5f, table );
  // patch the Oscil to the output
  wave.patch( out );
}

void draw()
{
  background(0);
  
  stroke(255, 64);
  strokeWeight(1);
  
  // draw the waveform of the output
  for(int i = 0; i < out.bufferSize() - 1; i++)
  {
    line( i, 50  - out.left.get(i)*50,  i+1, 50  - out.left.get(i+1)*50 );
    line( i, 150 - out.right.get(i)*50, i+1, 150 - out.right.get(i+1)*50 );
  }

  // draw the waveform we are using in the oscillator
  stroke( 200, 0, 0 );
  strokeWeight(4);
  for( int i = 0; i < width-1; ++i )
  {
    point( i, height/2 - (height*0.49) * table.value( (float)i / width ) );
  }
}

void keyPressed()
{ 
  switch( key )
  {
    case 'n':
      // scale the table so that the largest value is -1/1.
      table.normalize();
      break;
     
    case 's':
      // smooth out the table, similar to applying a low pass filter
      table.smooth( 64 );
      break;
     
    case 'r':
      // change all negative values to positive values
      table.rectify();
      break;
   
    case 'z':
      // add some noise
      table.addNoise( 0.1f );
      break;
    
    case 'q':
      table.scale( 1.1f );
      break;
      
    case 'a':
      table.scale( 0.9f );
      break;
     
    default: break; 
  }
}

void mousePressed()
{
  if ( mouseButton == RIGHT )
  {
    float flipPoint = map( mouseY, 0, height, 1, -1 );
    table.flip( flipPoint );
  }
}

void mouseDragged()
{
  if ( mouseButton == LEFT )
  {
    float warpPoint = constrain( (float)pmouseX / width, 0, 1 );
    float warpTarget = constrain( (float)mouseX / width, 0, 1 );
    table.warp( warpPoint, warpTarget );
  }
}

Usage

Web & Application